588 Wisconsin Academy of Sciences, Arts, and Letters. 
segment is of the same length, but slightly wider posteriorly. 
The anterior transverse folds are well marked. The abdomen in¬ 
creases very slightly in width for one half of its length and then 
tapers gradually to the foot. The tail projects very slightly on 
the dorsal side. The foot has but a single, very stout, joint. The 
toes are short, about one fifteenth of the total length, stout, coni¬ 
cal, and acutely pointed. 
The dorsal and lateral antennae are minute setigerous papillae 
in the normal positions. 
The corona extends down on the ventral side nearly one third 
of the length of the body; the post-oral portion projects from the 
ventral side of the body as a slight chin. The auricles are small, 
and the ciliation is continuous with the corona. 
The mastax is virgate, and the trophi are of relatively simple 
form without conspicuous asymmetry. The fulcrum is relatively 
short, slender, and slightly tapering; the posterior end is some¬ 
what incurved and slightly enlarged for the attachment of the 
muscles. The rami are nearly semicircular in ventral view and 
very slightly curved toward the dorsal side at the anterior ex¬ 
tremity. The inner edges are smooth, without any trace of den- 
ticulation. The right uncus has five, and the left uncus four, 
straight teeth, slightly clubbed at the point and gradually de¬ 
creasing in size toward the dorsal margin. The anterior end of 
the manubrium is moderately expanded, the posterior slender and 
nearly straight, with an external, membranous keel. Two rela¬ 
tively large, roughly triangular epipharyngeal pieces aid in the 
support of the mouth during the pumping action. 
The oesophagus is rather short and slender. The gastric 
glands, stomach-intestine, and ovary are normal. The bladder 
appears to be formed by an expansion of the cloaca. The foot 
glands are very large, elongate-ovate, and terminate in a very 
small mucus reservoir at the base of the toes. The retrocerebral 
sac is moderately large and ovate, while the subcerebral glands 
are unusually large and pyriform; no bacteroids are present. The 
eye-spot is at the posterior end of the saccate ganglion. 
Total length 130/a; toes 9/a; trophi 30/a. 
Notommata placida has been found only in small numbers in 
weedy ponds at Kenilworth, near Washington, District of Colum¬ 
bia. While without any striking external characteristics, it 
should be readily recognized by the general form of the body, 
